To find beta testers for your app, consider leveraging various online platforms and communities, such as Hacker News, Reddit, Product Hunt, and startup directories, where tech enthusiasts and early adopters congregate. These platforms can provide valuable feedback and help you reach a large audience interested in your domain. It's essential to follow community rules and guidelines when sharing your product, as users may be hesitant to engage with unsolicited content. By targeting the right communities and being authentic in your approach, you can find willing beta testers who will provide constructive feedback to improve your app.